1. Field of the Invention
The present invention relates to a dispensing valve intended to be mounted to a dispenser including a container capable of containing a product stored under pressure, particularly using a propellant gas. The invention also relates to a dispenser equipped with such a valve. This dispenser is more specifically intended for the packaging and dispensing of a fluid product such as a cosmetic, dermatological, household or food product or a workshop product, such as for example a hair lacquer, a disinfectant spray, a paint or a cleaning product. The valve according to the invention may be of the tilt type or the push-in type. It may be of the male or female type. The container on which it is to be fitted can operate head up or head down. The product to be dispensed may be pressurized by compressed (non-liquefiable) gas, by liquefiable gas, or by a piston. The gas may be nitrogen or butane.
2. Description of the Related Art
Typically, a valve consists of a valve body having an inlet passage and an outlet passage, a shut-off element for placing the inlet passage in communication with the outlet passage in response to an actuation, and an elastic return part for otherwise urging the shut-off element into the closed position.
Such valves may be equipped with an Additional Gas Intake (AGI) in the form of an orifice in the valve body and opening into the upper part of a container on which the valve is mounted, which upper part contains gas used to pressurize the liquid product. The AGI has the function of enriching the dispensed mixture with gas, which may be desirable particularly when dispensing a product in the form of a mousse or foam. Likewise, when the container is intended to operate head up, a dip tube is mounted on the valve body, one of the ends of the valve body being connected to the inlet passage of the valve body, the other end being situated more or less at the bottom of the reservoir.
Forming such an AGI and mounting a dip tube presents no difficulties when the valve body is made of a rigid or semi-rigid material such as a metal or a plastic of the polypropylene type. However, there is known from FR-A-2,161,350 a valve comprising an operating stem arranged in a valve body formed of an elastomeric material. Actuation of this valve is achieved by pushing the operating stem in axially against elastic return element. The dip tube is fixed directly to the elastomeric valve body.
Another valve of this type is described in DE-A-1,037,377. According to this document, the shut-off element has a rounded end portion of a valve stem which when tilted, causes the inlet passage to be placed in communication with the outlet passage. According to this document, the dip tube is integral with the free edge delimited by the inlet passage of the valve body. According to a particular embodiment, the dip tube forms a single entity with the valve body.
Experience has shown that having the dip tube mounted directly on the elastic valve body is not satisfactory. In practice, because of the substantial pressures inside the container, sufficiently secure attachment is difficult or impossible to achieve. Furthermore, when the valve opens, in the case of attachment as described in DE-A-1,037,377, the dip tube is subjected to relatively high stress which runs the risk of damaging it or detaching it from the valve body. What is more, it is practically impossible to produce an orifice in the elastic valve body to achieve an AGI, because of the nature of the material. In such a material, it is actually necessary to produce an orifice of a relatively large diameter in order to achieve an effective AGI. This large-diameter orifice is, however, prejudicial to the dispensing of product.
U.S. Pat. No. 3,618,832 discloses a valve made from an elastomeric material and having a valve stem which has a first portion emerging from the container so as to allow the product to be dispensed, and a second portion opposite the first, arranged in the inlet passage of the valve body and extending inside the container above the surface of the liquid. An additional gas intake is provided in the form of a passage formed axially between the exterior surface of the stem portion arranged in the inlet passage and a corresponding portion of the elastomeric valve body. One of the problems associated with a design of this kind stems from the fact that the passage thus produced is at least partially delimited by the valve body which is made of an elastomeric material, which is subject to variations in flexibility or to swelling which will alter the flow rate of additional gas entering the valve. Furthermore, even if it were not desirable to have an additional gas intake when actuating the valve, an undesirable inlet of gas between said second portion of the valve stem and the corresponding portion of the valve body would likely occur.